impregnability

Noun

uncountable

The quality or state of being impregnable; invincibility.

Japanese Meaning

侵入不可能な状態 / 無敵性 / 守りが堅固で攻撃を受け付けない性質

The fortress's impregnability impressed even the most seasoned generals.

その要塞の難攻不落の性質は、最も経験豊富な将軍たちさえ感銘を受けた。

Sense（1）

The quality or state of being impregnable; invincibility.